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from the Center to the Circumference. When this Infed 
flops itfelf any where, it holds flrongly by means of 
this Protuberance. Before it applies it, it fhortens it, 
by withdrawing the Edges, or the Circumference to- 
wards its Centre , and after it has applied the Orifice 
of its Protuberance upon the Surface of any Body, it 
lifts up a little the Center, or Bottom, towards its own 
Body afterwards it fwells it, and ftretches it on all 
Sides, according to all its Dimenfions. This Protube- 
rance thus applied, flretched and void of Air, makes 
that which endeavours to enter, prefs it externally on 
all Sides, and hold it fo fall, that it is above the 
Strength of the Animal to feparate it from it’s Place 
where it is applied. I'his Animal being thus faflened, 
and detained by it’s Protuberance, it’s fore Part ,is al- 
ways in Motion, whilfl its hinder Part remains almoft 
immoveable. It ftretches it’s Head fometimes to the 
Right Hand, fometimes to the Left, by lengthening 
and ftiortening its fore Part, which bends and ftreight- 
ens itfelf very frequently. I have marked the Ex- 
tent of all thefe Motions by prickt Circles of differ- 
ent BignelTes, all which touch one another at one 
Point of their Circumference, at the Center of the Pro- 
tuberance, which is as it were the Beginning and fixed 
Point of all thefe Motions. Thefe Circles thus dif- 
pofed are excentric, contained one within the other. 
It is by thefe different Motions that this Infed per- 
forms the two Funftions which are necelTary to it. 
I, To find the moft convenient Way when it has a 
Mind to change its Place. To difcover the moft 
proper Place, either upon or within the Body of the 
Ftfh’i where it finds itfelf faftened,. to fuck the Blood, 
■or 
